Semiconductor device fabrication techniques for use with a silicon substrate have been under development and in commercial use for many years. It is the existence of this wealth of device technology (whereby metal-oxide-semiconductor (MOS) elements may be fabricated on a silicon substrate so as to have practically any desired electrical characteristic) which has made silicon fundamental to a large class of imaging devices. Furthermore, there are other semiconductor materials in addition to silicon for which imaging devices such as the present invention should find utility--especially as improved fabrication technologies become commercially available for such other semiconductors. Among such other semiconductor materials may be listed, for instance, germanium, indium antimonide and gallium arsenide.
Critical design and fabrication considerations for monolithic arrays of semiconductor infrared photodetectors comprise three areas: (A) Extrinsic Detector Considerations, (B) Cryogenic Considerations and (C) Fabrication Considerations.